This invention relates generally to air conditioning systems and, more particularly, to an improved method and apparatus for controlling the humidity in a space.
With conventional air conditioning systems, little effort is made to control the humidity in the space being cooled and, as a result, in order to achieve the degree of desired comfort, it is necessary to bring the space down to a lower temperature than would otherwise be required. Such an "over cooling" function is relatively expensive and also may be cause for discomfort to one in the space being cooled.
An improvement was made to the conventional air conditioning system by the addition of a subcooler on the downstream side of the evaporator as shown and described in U.S. Pat. No. 5,622,057, issued on Apr. 22, 1997. Here, the latent effect of the evaporator coil is enhanced by the added subcooler coil, and the humidity is substantially reduced.
Another approach that has been taken to control humidity in a space is that of using desiccants to supplement the conventional air conditioning system. Such a system is shown in U.S. Pat. No. 5,551,245, issued on Sep. 3, 1996. Although such a desiccant system can provide even greater humidity control than that of the subcooler approach mentioned above, the fabrication and installation costs thereof are substantially greater.
Because of the tight construction of buildings erected today, there is now the condition known as the "sick building" syndrome, wherein there is insufficient leakage of outside air into the building such that the same air is recycled over and over and becomes stale and stagnant. To avoid this problem, there is now an ASHRAE standard code establishing prescribed requirements for minimum replenishment of air volumes in public buildings. This is presently being accomplished by the use of economizers, but present systems will not accommodate the use of 100% outside air since the cooling capacity is generally not sufficient to do so. Similarly, a make-up air pre-conditioner is shown in U.S. Pat. No. 4,281,522, wherein a supplementary system is used to pre-cool the outdoor air. Again, such a system is not capable of accommodating 100% outside air
It is therefore an object of the present invention to provide an improved method and apparatus for the control of humidity in an air conditioned space.
Another object of the present invention is the provision for ensuring that the air in a building does not become stale.
Yet another object of the present invention is the provision for controlling humidity in an economical and effective manner.
Still another object of the present invention is the provision for the effective and economical use of up to 100% of outside make-up air.
These objects and other features and advantages become more readily apparent upon reference to the following description when taken in conjunction with the appended drawings.